79 research outputs found
Information extraction and transmission techniques for spaceborne synthetic aperture radar images
Information extraction and transmission techniques for synthetic aperture radar (SAR) imagery were investigated. Four interrelated problems were addressed. An optimal tonal SAR image classification algorithm was developed and evaluated. A data compression technique was developed for SAR imagery which is simple and provides a 5:1 compression with acceptable image quality. An optimal textural edge detector was developed. Several SAR image enhancement algorithms have been proposed. The effectiveness of each algorithm was compared quantitatively
Pyruvate Formate Lyase and Acetate Kinase are Essential for Anaerobic Growth of \u3cem\u3eEscherichia coli\u3c/em\u3e on Xylose
During anaerobic growth of bacteria, organic intermediates of metabolism, such as pyruvate or its derivatives, serve as electron acceptors to maintain the overall redox balance. Under these conditions, the ATP needed for cell growth is derived from substrate-level phosphorylation. In Escherichia coli, conversion of glucose to pyruvate yields 2 net ATPs, while metabolism of a pentose, such as xylose, to pyruvate only yields 0.67 net ATP per xylose due to the need for one (each) ATP for xylose transport and xylulose phosphorylation. During fermentative growth, E. coli produces equimolar amounts of acetate and ethanol from two pyruvates, and these reactions generate one additional ATP from two pyruvates (one hexose equivalent) while still maintaining the overall redox balance. Conversion of xylose to acetate and ethanol increases the net ATP yield from 0.67 to 1.5 per xylose. An E. coli pfl mutant lacking pyruvate formate lyase cannot convert pyruvate to acetyl coenzyme A, the required precursor for acetate and ethanol production, and could not produce this additional ATP. E. coli pfl mutants failed to grow under anaerobic conditions in xylose minimal medium without any negative effect on their survival or aerobic growth. An ackA mutant, lacking the ability to generate ATP from acetyl phosphate, also failed to grow in xylose minimal medium under anaerobic conditions, confirming the need for the ATP produced by acetate kinase for anaerobic growth on xylose. Since arabinose transport by AraE, the low-affinity, high-capacity, arabinose/H+ symport, conserves the ATP expended in pentose transport by the ABC transporter, both pfl and ackA mutants grew anaerobically with arabinose. AraE-based xylose transport, achieved after constitutively expressing araE, also supported the growth of the pfl mutant in xylose minimal medium. These results suggest that a net ATP yield of 0.67 per pentose is only enough to provide for maintenance energy but not enough to support growth of E. coli in minimal medium. Thus, pyruvate formate lyase and acetate kinase are essential for anaerobic growth of E. coli on xylose due to energetic constraints
Multilevel analysis of systolic blood pressure and ACE gene I/D polymorphism in 438 Swedish families – a public health perspective
BACKGROUND: Individuals belonging to the same family share a number of genetic as well as environmental circumstances that may condition a common SBP level. Among the genetic factors, the angiotensin converting enzyme (ACE) gene I/D polymorphism appears as a possible candidate as it might influence both SBP and the pharmacological effect of ACE inhibitors. We aimed to combine genetic epidemiology with public health ideas concerning life-course and multilevel epidemiology in order to understand the role of familial factors regarding individual SBP. METHODS: We applied multilevel regression analysis on 1926 individuals nested within 438 families from South Sweden. Modelling familial SBP variance as a function of age and use of ACE inhibitors we calculates a variance partition coefficient and the proportional change in familial SBP variance attributable to differences in ACE gene I/D polymorphism RESULTS: Our results suggest the existence of genetic or environmental circumstances that produce a considerable familial clustering of SBP, especially among individuals using ACE-inhibitors. However, ACE gene I/D polymorphism seems to play a minor role in this context. In addition, familial factors – genetic, environmental or their interaction – shape SBP among non-users of ACE inhibitors but their effect is expressed later in the life-course. CONCLUSION: Strategies directed to prevent hypertension should be launched in younger rather than in older ages and both prevention of hypertension and its treatment with ACE inhibitors should be focused on families rather than on individuals
The Rapidly Deployable Radio Network
The Rapidly Deployable Radio Network (RDRN) is an architecture and experimental system to develop and evaluate hardware and software components suitable for implementing mobile, rapidly deployable, and adaptive wireless communications systems. The driving application for the RDRN is the need to quickly establish a communications infrastructure following a natural disaster, during a law enforcement activity, or rapid deployment of military force. The RDRN project incorporates digitally controlled antenna beams, programmable radios, adaptive protocols at the link layer, and mobile node management. This paper describes the architecture for the Rapidly Deployable Radio Network and a prototype system built to evaluate key system components
Probable late Messinian tsunamiites near Monte Dei Corvi, Italy, and the Nijar Basin, Spain: expected architecture of offshore tsunami deposits
Culture of fishes in cages and pens along the coastal waters of India
The results of culture attempts of milkfish, Chanos chanos, Mugil spp., prawn Penaeus indicus and crab Scylla serrata in enclosures of bamboo splits (thatti), fixed in shallow inshore waters at Tuticorin, are summarized
Structural Diversity in Zinc Phosphates and Phosphinates: Observation of a Lattice Water Dimer Sandwiched Between Phosphoryl Oxygen Atoms
Reactions of zinc acetate dihydrate with organic phosphates (R = tBu, Ph) and phosphinic acids [PhR'P(O)(OH)] (R' = Ph, H) have been investigated in the presence of 1,10-phenanthroline (phen). While the use of ditert-butyl phosphate (dtbp-H) results in the formation of (1), the change of phosphorus source to diphenylphosphate (dpp-H) yields an interesting phosphate-bridged dinuclear complex (2). Mononuclear complexes (3) and (4) have been obtained from similar reactions by the use of diphenylphosphinic acid (dppi-H) and phenylphosphinic acid (ppi-H), respectively. The high steric bulk of the dtbp ligand results in the formation of the cationic complex 1, where only one of the dtbp ligands is directly coordinated to the metal atom, leaving the second dtbp molecule as the counter anion. The inorganic core of dinuclear zinc phosphate 2 resembles the single four-ring (S4R) secondary building unit of framework zinc phosphates. Compounds 3 and 4 are neutral monomeric hexacoordinate complexes with two chelating 1,10-phen ligands and two monodentate phosphinate ligands. The two lattice water molecules in 3 form an interesting water dimer . These water dimers link the mononuclear zinc complexes in the lattice to form an Hbonded one-dimensional polymer. Similarly, the lattice water present in 4 serves to link the zinc phenylphosphinate molecules through hydrogen bonding in the form of a 1-D polymer. The reaction of the precursor complex with dpp-H, dppi-H, and ppi-H in methanol leads to the formation of zinc phosphate (5) and phosphinates (6) and (7), respectively. The molecular structures of 1–5 and 7 have been determined by singlecrystal X-ray diffraction studies
Modeling multimedia displays using action based temporal logic
Abstract We present a metalanguage, named Alan that can be used to model dynamic multimedia displays, particularly those that display multimedia database query results. Alan is an action language that uses temporal logic to model non-Markovian systems. We show how it can be used for specifying the behavior of fairly complex dynamic multimedia display systems, modeling all graphical user interface elements on the display plus the effects of actions and of the passage of time on media such as video and audio
Empirically derived path reduction factor for terrestrial microwave links operating at 15 Ghz In Peninsular Malaysia
This paper describes the technique of deriving path reduction factor from experimental rain rate and rain attenuation data over seven DIGI MINI-LINKs operating at 15 GHz in Malaysia (Lat.: 1.45°N and Long.: 103.75°E). The relationship between experimental path reduction factors with different link lengths has been studied, using multiple non-linear curve-fitting techniques. Based on these studies, an empirical path reduction factor model has been proposed and compared with the ITU-R model. The test results have shown that the ITU-R prediction model may not be appropriate for predicting rain-induced attenuation for the tropical Malaysian climate
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